The Devils Tuning Fork

You get one brief, make a game using echo location as the game mechanic.
How do you proceed from that?

Well, a group of students took that challenge and made an interesting concept for a puzzle game, using a first person mode you navigate the levels in pitch black, using a tuning fork (the Devil’s Tuning Fork) to send out an audio-wave across the level, you only see everything for a couple of seconds and then darkness again.
Using this very simple mechanic you have to get through the world, saving the spirits of lost children, it sounds simple doesn’t it? But it gets more complicated and is quite fun.

It isn’t by any means a long game, but it is a fun game and it’s free.